List data set: List the data set and understand what is being asked.The data set given is: −5,−6,−7,−7,−4,−6,−7,−4,−8. We are asked to find the mean (average) of these numbers.
Add numbers for sum: Add up all the numbers in the data set to find the sum. Sum = (−5)+(−6)+(−7)+(−7)+(−4)+(−6)+(−7)+(−4)+(−8)Sum = −54
Count values: Count the number of values in the data set.There are 9 numbers in the data set.
Divide sum for mean: Divide the sum by the number of values to find the mean.Mean = Number of valuesSumMean = 9(–54)Mean = –6